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i2c-core-acpi.c 18.16 KiB
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Linux I2C core ACPI support code
*
* Copyright (C) 2014 Intel Corp, Author: Lan Tianyu <tianyu.lan@intel.com>
*/
#include <linux/acpi.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/slab.h>
#include "i2c-core.h"
struct i2c_acpi_handler_data {
struct acpi_connection_info info;
struct i2c_adapter *adapter;
};
struct gsb_buffer {
u8 status;
u8 len;
union {
u16 wdata;
u8 bdata;
u8 data[0];
};
} __packed;
struct i2c_acpi_lookup {
struct i2c_board_info *info;
acpi_handle adapter_handle;
acpi_handle device_handle;
acpi_handle search_handle;
int n;
int index;
u32 speed;
u32 min_speed;
u32 force_speed;
};
/**
* i2c_acpi_get_i2c_resource - Gets I2cSerialBus resource if type matches
* @ares: ACPI resource
* @i2c: Pointer to I2cSerialBus resource will be returned here
*
* Checks if the given ACPI resource is of type I2cSerialBus.
* In this case, returns a pointer to it to the caller.
*
* Returns true if resource type is of I2cSerialBus, otherwise false.
*/
bool i2c_acpi_get_i2c_resource(struct acpi_resource *ares,
struct acpi_resource_i2c_serialbus **i2c)
{
struct acpi_resource_i2c_serialbus *sb;
if (ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS)
return false;
sb = &ares->data.i2c_serial_bus;
if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_I2C)
return false;
*i2c = sb;
return true;
}
EXPORT_SYMBOL_GPL(i2c_acpi_get_i2c_resource);
static int i2c_acpi_fill_info(struct acpi_resource *ares, void *data)
{
struct i2c_acpi_lookup *lookup = data;
struct i2c_board_info *info = lookup->info;
struct acpi_resource_i2c_serialbus *sb;
acpi_status status;
if (info->addr || !i2c_acpi_get_i2c_resource(ares, &sb))
return 1;
if (lookup->index != -1 && lookup->n++ != lookup->index)
return 1;
status = acpi_get_handle(lookup->device_handle,
sb->resource_source.string_ptr,
&lookup->adapter_handle);
if (ACPI_FAILURE(status))
return 1;
info->addr = sb->slave_address;
lookup->speed = sb->connection_speed;
if (sb->access_mode == ACPI_I2C_10BIT_MODE)
info->flags |= I2C_CLIENT_TEN;
return 1;
}
static const struct acpi_device_id i2c_acpi_ignored_device_ids[] = {
/*
* ACPI video acpi_devices, which are handled by the acpi-video driver
* sometimes contain a SERIAL_TYPE_I2C ACPI resource, ignore these.
*/
{ ACPI_VIDEO_HID, 0 },
{}
};
static int i2c_acpi_do_lookup(struct acpi_device *adev,
struct i2c_acpi_lookup *lookup)
{
struct i2c_board_info *info = lookup->info;
struct list_head resource_list;
int ret;
if (acpi_bus_get_status(adev) || !adev->status.present)
return -EINVAL;
if (acpi_match_device_ids(adev, i2c_acpi_ignored_device_ids) == 0)
return -ENODEV;
memset(info, 0, sizeof(*info));
lookup->device_handle = acpi_device_handle(adev);
/* Look up for I2cSerialBus resource */
INIT_LIST_HEAD(&resource_list);
ret = acpi_dev_get_resources(adev, &resource_list,
i2c_acpi_fill_info, lookup);
acpi_dev_free_resource_list(&resource_list);
if (ret < 0 || !info->addr)
return -EINVAL;
return 0;
}
static int i2c_acpi_add_resource(struct acpi_resource *ares, void *data)
{
int *irq = data;
struct resource r;
if (*irq <= 0 && acpi_dev_resource_interrupt(ares, 0, &r))
*irq = i2c_dev_irq_from_resources(&r, 1);
return 1; /* No need to add resource to the list */
}
/**
* i2c_acpi_get_irq - get device IRQ number from ACPI
* @client: Pointer to the I2C client device
*
* Find the IRQ number used by a specific client device.
*
* Return: The IRQ number or an error code.
*/
int i2c_acpi_get_irq(struct i2c_client *client)
{
struct acpi_device *adev = ACPI_COMPANION(&client->dev);
struct list_head resource_list;
int irq = -ENOENT;
int ret;
INIT_LIST_HEAD(&resource_list);
ret = acpi_dev_get_resources(adev, &resource_list,
i2c_acpi_add_resource, &irq);
if (ret < 0)
return ret;
acpi_dev_free_resource_list(&resource_list);
if (irq == -ENOENT)
irq = acpi_dev_gpio_irq_get(adev, 0);
return irq;
}
static int i2c_acpi_get_info(struct acpi_device *adev,
struct i2c_board_info *info,
struct i2c_adapter *adapter,
acpi_handle *adapter_handle)
{
struct i2c_acpi_lookup lookup;
int ret;
memset(&lookup, 0, sizeof(lookup));
lookup.info = info;
lookup.index = -1;
if (acpi_device_enumerated(adev))
return -EINVAL;
ret = i2c_acpi_do_lookup(adev, &lookup);
if (ret)
return ret;
if (adapter) {
/* The adapter must match the one in I2cSerialBus() connector */
if (ACPI_HANDLE(&adapter->dev) != lookup.adapter_handle)
return -ENODEV;
} else {
struct acpi_device *adapter_adev;
/* The adapter must be present */
if (acpi_bus_get_device(lookup.adapter_handle, &adapter_adev))
return -ENODEV;
if (acpi_bus_get_status(adapter_adev) ||
!adapter_adev->status.present)
return -ENODEV;
}
info->fwnode = acpi_fwnode_handle(adev);
if (adapter_handle)
*adapter_handle = lookup.adapter_handle;
acpi_set_modalias(adev, dev_name(&adev->dev), info->type,
sizeof(info->type));
return 0;
}
static void i2c_acpi_register_device(struct i2c_adapter *adapter,
struct acpi_device *adev,
struct i2c_board_info *info)
{
adev->power.flags.ignore_parent = true;
acpi_device_set_enumerated(adev);
if (!i2c_new_device(adapter, info)) {
adev->power.flags.ignore_parent = false;
dev_err(&adapter->dev,
"failed to add I2C device %s from ACPI\n",
dev_name(&adev->dev));
}
}
static acpi_status i2c_acpi_add_device(acpi_handle handle, u32 level,
void *data, void **return_value)
{
struct i2c_adapter *adapter = data;
struct acpi_device *adev;
struct i2c_board_info info;
if (acpi_bus_get_device(handle, &adev))
return AE_OK;
if (i2c_acpi_get_info(adev, &info, adapter, NULL))
return AE_OK;
i2c_acpi_register_device(adapter, adev, &info);
return AE_OK;
}
#define I2C_ACPI_MAX_SCAN_DEPTH 32
/**
* i2c_acpi_register_devices - enumerate I2C slave devices behind adapter
* @adap: pointer to adapter
*
* Enumerate all I2C slave devices behind this adapter by walking the ACPI
* namespace. When a device is found it will be added to the Linux device
* model and bound to the corresponding ACPI handle.
*/
void i2c_acpi_register_devices(struct i2c_adapter *adap)
{
acpi_status status;
if (!has_acpi_companion(&adap->dev))
return;
status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
I2C_ACPI_MAX_SCAN_DEPTH,
i2c_acpi_add_device, NULL,
adap, NULL);
if (ACPI_FAILURE(status))
dev_warn(&adap->dev, "failed to enumerate I2C slaves\n");
}
const struct acpi_device_id *
i2c_acpi_match_device(const struct acpi_device_id *matches, struct i2c_client *client)
{
if (!(client && matches))
return NULL;
return acpi_match_device(matches, &client->dev);
}
static const struct acpi_device_id i2c_acpi_force_400khz_device_ids[] = {
/*
* These Silead touchscreen controllers only work at 400KHz, for
* some reason they do not work at 100KHz. On some devices the ACPI
* tables list another device at their bus as only being capable
* of 100KHz, testing has shown that these other devices work fine
* at 400KHz (as can be expected of any recent i2c hw) so we force
* the speed of the bus to 400 KHz if a Silead device is present.
*/
{ "MSSL1680", 0 },
{}
};
static acpi_status i2c_acpi_lookup_speed(acpi_handle handle, u32 level,
void *data, void **return_value)
{
struct i2c_acpi_lookup *lookup = data;
struct acpi_device *adev;
if (acpi_bus_get_device(handle, &adev))
return AE_OK;
if (i2c_acpi_do_lookup(adev, lookup))
return AE_OK;
if (lookup->search_handle != lookup->adapter_handle)
return AE_OK;
if (lookup->speed <= lookup->min_speed)
lookup->min_speed = lookup->speed;
if (acpi_match_device_ids(adev, i2c_acpi_force_400khz_device_ids) == 0)
lookup->force_speed = 400000;
return AE_OK;
}
/**
* i2c_acpi_find_bus_speed - find I2C bus speed from ACPI
* @dev: The device owning the bus
*
* Find the I2C bus speed by walking the ACPI namespace for all I2C slaves
* devices connected to this bus and use the speed of slowest device.
*
* Returns the speed in Hz or zero
*/
u32 i2c_acpi_find_bus_speed(struct device *dev)
{
struct i2c_acpi_lookup lookup;
struct i2c_board_info dummy;
acpi_status status;
if (!has_acpi_companion(dev))
return 0;
memset(&lookup, 0, sizeof(lookup));
lookup.search_handle = ACPI_HANDLE(dev);
lookup.min_speed = UINT_MAX;
lookup.info = &dummy;
lookup.index = -1;
status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT, I2C_ACPI_MAX_SCAN_DEPTH,
i2c_acpi_lookup_speed, NULL,
&lookup, NULL);
if (ACPI_FAILURE(status)) {
dev_warn(dev, "unable to find I2C bus speed from ACPI\n");
return 0;
}
if (lookup.force_speed) {
if (lookup.force_speed != lookup.min_speed)
dev_warn(dev, FW_BUG "DSDT uses known not-working I2C bus speed %d, forcing it to %d\n",
lookup.min_speed, lookup.force_speed);
return lookup.force_speed;
} else if (lookup.min_speed != UINT_MAX) {
return lookup.min_speed;
} else {
return 0;
}
}
EXPORT_SYMBOL_GPL(i2c_acpi_find_bus_speed);
static int i2c_acpi_find_match_adapter(struct device *dev, const void *data)
{
struct i2c_adapter *adapter = i2c_verify_adapter(dev);
if (!adapter)
return 0;
return ACPI_HANDLE(dev) == (acpi_handle)data;
}
struct i2c_adapter *i2c_acpi_find_adapter_by_handle(acpi_handle handle)
{
struct device *dev;
dev = bus_find_device(&i2c_bus_type, NULL, handle,
i2c_acpi_find_match_adapter);
return dev ? i2c_verify_adapter(dev) : NULL;
}
EXPORT_SYMBOL_GPL(i2c_acpi_find_adapter_by_handle);
static struct i2c_client *i2c_acpi_find_client_by_adev(struct acpi_device *adev)
{
struct device *dev;
dev = bus_find_device_by_acpi_dev(&i2c_bus_type, adev);
return dev ? i2c_verify_client(dev) : NULL;
}
static int i2c_acpi_notify(struct notifier_block *nb, unsigned long value,
void *arg)
{
struct acpi_device *adev = arg;
struct i2c_board_info info;
acpi_handle adapter_handle;
struct i2c_adapter *adapter;
struct i2c_client *client;
switch (value) {
case ACPI_RECONFIG_DEVICE_ADD:
if (i2c_acpi_get_info(adev, &info, NULL, &adapter_handle))
break;
adapter = i2c_acpi_find_adapter_by_handle(adapter_handle);
if (!adapter)
break;
i2c_acpi_register_device(adapter, adev, &info); break;
case ACPI_RECONFIG_DEVICE_REMOVE:
if (!acpi_device_enumerated(adev))
break;
client = i2c_acpi_find_client_by_adev(adev);
if (!client)
break;
i2c_unregister_device(client);
put_device(&client->dev);
break;
}
return NOTIFY_OK;
}
struct notifier_block i2c_acpi_notifier = {
.notifier_call = i2c_acpi_notify,
};
/**
* i2c_acpi_new_device - Create i2c-client for the Nth I2cSerialBus resource
* @dev: Device owning the ACPI resources to get the client from
* @index: Index of ACPI resource to get
* @info: describes the I2C device; note this is modified (addr gets set)
* Context: can sleep
*
* By default the i2c subsys creates an i2c-client for the first I2cSerialBus
* resource of an acpi_device, but some acpi_devices have multiple I2cSerialBus
* resources, in that case this function can be used to create an i2c-client
* for other I2cSerialBus resources in the Current Resource Settings table.
*
* Also see i2c_new_device, which this function calls to create the i2c-client.
*
* Returns a pointer to the new i2c-client, or error pointer in case of failure.
* Specifically, -EPROBE_DEFER is returned if the adapter is not found.
*/
struct i2c_client *i2c_acpi_new_device(struct device *dev, int index,
struct i2c_board_info *info)
{
struct i2c_acpi_lookup lookup;
struct i2c_adapter *adapter;
struct i2c_client *client;
struct acpi_device *adev;
LIST_HEAD(resource_list);
int ret;
adev = ACPI_COMPANION(dev);
if (!adev)
return ERR_PTR(-EINVAL);
memset(&lookup, 0, sizeof(lookup));
lookup.info = info;
lookup.device_handle = acpi_device_handle(adev);
lookup.index = index;
ret = acpi_dev_get_resources(adev, &resource_list,
i2c_acpi_fill_info, &lookup);
if (ret < 0)
return ERR_PTR(ret);
acpi_dev_free_resource_list(&resource_list);
if (!info->addr)
return ERR_PTR(-EADDRNOTAVAIL);
adapter = i2c_acpi_find_adapter_by_handle(lookup.adapter_handle);
if (!adapter)
return ERR_PTR(-EPROBE_DEFER);
client = i2c_new_device(adapter, info);
if (!client)
return ERR_PTR(-ENODEV);
return client;
}
EXPORT_SYMBOL_GPL(i2c_acpi_new_device);
#ifdef CONFIG_ACPI_I2C_OPREGION
static int acpi_gsb_i2c_read_bytes(struct i2c_client *client,
u8 cmd, u8 *data, u8 data_len)
{
struct i2c_msg msgs[2];
int ret;
u8 *buffer;
buffer = kzalloc(data_len, GFP_KERNEL);
if (!buffer)
return AE_NO_MEMORY;
msgs[0].addr = client->addr;
msgs[0].flags = client->flags;
msgs[0].len = 1;
msgs[0].buf = &cmd;
msgs[1].addr = client->addr;
msgs[1].flags = client->flags | I2C_M_RD;
msgs[1].len = data_len;
msgs[1].buf = buffer;
ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
if (ret < 0) {
/* Getting a NACK is unfortunately normal with some DSTDs */
if (ret == -EREMOTEIO)
dev_dbg(&client->adapter->dev, "i2c read %d bytes from client@%#x starting at reg %#x failed, error: %d\n",
data_len, client->addr, cmd, ret);
else
dev_err(&client->adapter->dev, "i2c read %d bytes from client@%#x starting at reg %#x failed, error: %d\n",
data_len, client->addr, cmd, ret);
/* 2 transfers must have completed successfully */
} else if (ret == 2) {
memcpy(data, buffer, data_len);
ret = 0;
} else {
ret = -EIO;
}
kfree(buffer);
return ret;
}
static int acpi_gsb_i2c_write_bytes(struct i2c_client *client,
u8 cmd, u8 *data, u8 data_len)
{
struct i2c_msg msgs[1];
u8 *buffer;
int ret = AE_OK;
buffer = kzalloc(data_len + 1, GFP_KERNEL);
if (!buffer)
return AE_NO_MEMORY;
buffer[0] = cmd;
memcpy(buffer + 1, data, data_len);
msgs[0].addr = client->addr;
msgs[0].flags = client->flags; msgs[0].len = data_len + 1;
msgs[0].buf = buffer;
ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
kfree(buffer);
if (ret < 0) {
dev_err(&client->adapter->dev, "i2c write failed: %d\n", ret);
return ret;
}
/* 1 transfer must have completed successfully */
return (ret == 1) ? 0 : -EIO;
}
static acpi_status
i2c_acpi_space_handler(u32 function, acpi_physical_address command,
u32 bits, u64 *value64,
void *handler_context, void *region_context)
{
struct gsb_buffer *gsb = (struct gsb_buffer *)value64;
struct i2c_acpi_handler_data *data = handler_context;
struct acpi_connection_info *info = &data->info;
struct acpi_resource_i2c_serialbus *sb;
struct i2c_adapter *adapter = data->adapter;
struct i2c_client *client;
struct acpi_resource *ares;
u32 accessor_type = function >> 16;
u8 action = function & ACPI_IO_MASK;
acpi_status ret;
int status;
ret = acpi_buffer_to_resource(info->connection, info->length, &ares);
if (ACPI_FAILURE(ret))
return ret;
client = kzalloc(sizeof(*client), GFP_KERNEL);
if (!client) {
ret = AE_NO_MEMORY;
goto err;
}
if (!value64 || !i2c_acpi_get_i2c_resource(ares, &sb)) {
ret = AE_BAD_PARAMETER;
goto err;
}
client->adapter = adapter;
client->addr = sb->slave_address;
if (sb->access_mode == ACPI_I2C_10BIT_MODE)
client->flags |= I2C_CLIENT_TEN;
switch (accessor_type) {
case ACPI_GSB_ACCESS_ATTRIB_SEND_RCV:
if (action == ACPI_READ) {
status = i2c_smbus_read_byte(client);
if (status >= 0) {
gsb->bdata = status;
status = 0;
}
} else {
status = i2c_smbus_write_byte(client, gsb->bdata);
}
break;
case ACPI_GSB_ACCESS_ATTRIB_BYTE:
if (action == ACPI_READ) {
status = i2c_smbus_read_byte_data(client, command); if (status >= 0) {
gsb->bdata = status;
status = 0;
}
} else {
status = i2c_smbus_write_byte_data(client, command,
gsb->bdata);
}
break;
case ACPI_GSB_ACCESS_ATTRIB_WORD:
if (action == ACPI_READ) {
status = i2c_smbus_read_word_data(client, command);
if (status >= 0) {
gsb->wdata = status;
status = 0;
}
} else {
status = i2c_smbus_write_word_data(client, command,
gsb->wdata);
}
break;
case ACPI_GSB_ACCESS_ATTRIB_BLOCK:
if (action == ACPI_READ) {
status = i2c_smbus_read_block_data(client, command,
gsb->data);
if (status >= 0) {
gsb->len = status;
status = 0;
}
} else {
status = i2c_smbus_write_block_data(client, command,
gsb->len, gsb->data);
}
break;
case ACPI_GSB_ACCESS_ATTRIB_MULTIBYTE:
if (action == ACPI_READ) {
status = acpi_gsb_i2c_read_bytes(client, command,
gsb->data, info->access_length);
} else {
status = acpi_gsb_i2c_write_bytes(client, command,
gsb->data, info->access_length);
}
break;
default:
dev_warn(&adapter->dev, "protocol 0x%02x not supported for client 0x%02x\n",
accessor_type, client->addr);
ret = AE_BAD_PARAMETER;
goto err;
}
gsb->status = status;
err:
kfree(client);
ACPI_FREE(ares);
return ret;
}
int i2c_acpi_install_space_handler(struct i2c_adapter *adapter)
{
acpi_handle handle;
struct i2c_acpi_handler_data *data;
acpi_status status;
if (!adapter->dev.parent) return -ENODEV;
handle = ACPI_HANDLE(adapter->dev.parent);
if (!handle)
return -ENODEV;
data = kzalloc(sizeof(struct i2c_acpi_handler_data),
GFP_KERNEL);
if (!data)
return -ENOMEM;
data->adapter = adapter;
status = acpi_bus_attach_private_data(handle, (void *)data);
if (ACPI_FAILURE(status)) {
kfree(data);
return -ENOMEM;
}
status = acpi_install_address_space_handler(handle,
ACPI_ADR_SPACE_GSBUS,
&i2c_acpi_space_handler,
NULL,
data);
if (ACPI_FAILURE(status)) {
dev_err(&adapter->dev, "Error installing i2c space handler\n");
acpi_bus_detach_private_data(handle);
kfree(data);
return -ENOMEM;
}
acpi_walk_dep_device_list(handle);
return 0;
}
void i2c_acpi_remove_space_handler(struct i2c_adapter *adapter)
{
acpi_handle handle;
struct i2c_acpi_handler_data *data;
acpi_status status;
if (!adapter->dev.parent)
return;
handle = ACPI_HANDLE(adapter->dev.parent);
if (!handle)
return;
acpi_remove_address_space_handler(handle,
ACPI_ADR_SPACE_GSBUS,
&i2c_acpi_space_handler);
status = acpi_bus_get_private_data(handle, (void **)&data);
if (ACPI_SUCCESS(status))
kfree(data);
acpi_bus_detach_private_data(handle);
}
#endif /* CONFIG_ACPI_I2C_OPREGION */